Plural liquid unit for grinding machines



May 6, 1952 v v c. c. ALVORD 2,595,559

PLURAL LIQUID UNIT FOR GRINDING MACHINES Filed April .28,y 1949 I 5 sheets-sheet 1 115 LV- 456 l5 #4 mi y v f AT TURA/EV May 6, 1952 c. c. ALvoRD PLURAI LIQUID UNIT FOR GRINDING MACHINES 5 sheets-shez 2 Filed April 28,

JNVENTOR. EHA/11.55 C'. A IVD/51D AT TURA/EV May 6, 1952 c. c. ALVORD 2,595,559

PLURAL LIQUID UNIT FOR GRINDING MACHINES I Filed Aprill28, i949 5 Sheets-Sheet 3 Il .L U

CN.596 76 656 i.:

. F/ G. E 45 F G'. E

INVENTOR.

CHAR/ E5 C. A/ VDRD BY f AT TR'NE Y May 6, 1952 c. c. ALvoRD 2,595,559

PLURAL LIQUID UNIT FOR GRINDING MACHINES 53e I 40 53al 521'; 43 52o 4i 37 74 10 f iff/:.11

IN VEN TOR.

C'f-/ARLES C'. A I VDRIJ ATTUR'NEV c. c. ALVORD 2,595,559

PLURAL. LIQUID UNIT FOR GRINDING MACHINES 5 Sheets-Sheet 5 May 6, 1952 Filed April 28, 1949 121 w l2 /2/ /zf 123 N INVENIOR.

I CHARLE5-C. AIVD/Q13 BY 76 U2 /f/ Q )we a; l j ATTURNEY yof, grinding machines. 'vention is to provide a unitary plural fluid sup- Patented May 6, 1952 PLURAL LIQUID UNIT FOR GRIN-DING lMACI-IINES .Charles C. Alvord, Worcester, Mass., assignor to Norton Company, Worcester, `Mass., a corporation of Massachusetts Application April 28, 1949, SerialNm 0,171

9 Claims. (Cl. 210-52) The `invention relatesto grinding machines and morel particularly to van apparatus for .applying a cooling uid to grinding wheels and to `the work piece .being ground.

In order to provide a clearer understanding of some of the objects and features of this invention, it has been found that by supplying a grinding fluid at a relatively high `pressure and relatively small volume to the place of contactbetween the grinding wheel and the'work piece being ground and to supply a coolant :fluid to the Work piece being ground to cool the same, a more eflcient higher rate of grinding operation may be obtained. It has been found that by such a plural fluid apparatus thatthe grinding wheel surface stands up longer. requires less frequent truing operations and can take much heavier cuts at increased rate .of feeds than previously. Such a grinding method and .apparatus is disclosed in the wprior United States `Patent to H. W. Wagner and G.. J. Wickstrom No. 2,434,679 dated January 20, 1948 and also in the-pending application by H. W. Wagner and G. .J. Wickstrom Serial No. 2,505 led January l5, 1948,now Patent Number 2,475,811, July 16, 1949.

One of the objects of this invention is to provide a simple and thoroughly practical plural fluid supplying. apparatus for a grinding *.machine. Another object of the` invention is to provide a unitary plural iiuid supplying apparatus which may be .of a suitable size and capacity for separately supplying a grinding fluid at a relatively high pressure and relatively low volume `and to supply a coolant fluid at a relatively low pressure and relativelyl large. volume vto `one or a plurality Another object of the inply apparatus `which may be 4readily applied to either .a new grinding machine as manufacture, or maybesupplied for convertinga grinding machine or Vmachines in the eld for a plural fluid grinding method.

Another object of the invention is vto Aprovide a compact unitary plural fluid unit which serves to `settle-out yswarffrom the refuse uid returning from the grinding machine and to facilitate a separation of the grinding riiuid from the cooling fluid s-o that they may be again reconveyed to the grinding machine or machines Vfor further grindingioperations.

Another object ofV the invention is to employ a grinding fluid which is insoluble in the cooling fluid and which readily separates therefrom during gravity flow through the unit at substantially normal room temperature. Another object iS to provide a unit :sufficiently .large in. size to contain a large volume of both a grinding fluid. ,and .a cooling. fluid so that the fluids in the unit remain at substantially .normal room temperature Aduring operation.

The invention Vaccordingly consists in the features of construction, combinations Vof elements, and arrangements of parts, as will be exemplified inthe structure to be .hereinafter described, .and vthe scope of the application of which will he indicated in the following claims.

In the accompanying .drawings in which is shownfone of various `possible kembodiments .of the mechanical features of this invention,

Fig, lis `an `end elevation .of .the unitary plural fluid unit for grinding machines;

Fig. 2 is a front Yelevation ofthe unitary plural uid unit, partly broken away .to .show .the .levels ofthe two fluids in. the unit;

Fig. 3 is a 4fragmentary perspective view .of :the trays used in the upper portion of the unit;

Fig. v4 is a .fragmentary .pl-an view of the unit, as .shown in Fig. 1;

Fig. 5 .is a cross sectional view, .taken approximately on the line 5--5 of Fig. 4;

Fig. 6 is a similar cross sectional View, taken .approximately on the line E-6 of Fig. 4, partly broken away;

Fig. 7 is a similar cross sectional View, taken approximately on the line 'lh-1 of Fig. 4, partly broken away;

Fg.r8 is .a similar cross sectional View, taken approximately onthe line `88 of Fig. 4, partly broken away;

Fig. 9 `is 1a .fragmentary sectional view, on an enlarged scale, taken .approximately on the line 9-5 of Fig."7;

Fig. l0 .is .a plan view of the lower or tank section ofthe unit, with .the .upper portion-or pan thereof removed;

Fig. 11 is a fragmentary perspective view of some of 'the partitions and spaces used in the lower portionA or tank of the unit;

Fig. l2 is a piping diagram, showing the unit connected for si'pplying a grinding firid and a cooling fluid to a plurality of grinding machines; and

Fig. l'3 is an elementary electrical wiring dianlram ef the ccntrolsv for the fluid pump driving motor.

A unitary plural Afluid `unit I0 isillustrated in the drawings comprising a fluid tank Il which is ysupported by a plurality of spaced brackets I2, 1'3 and i4. The tank Il serves as a support for a setting tank i5. The tank ll serves to contain a supply of cooling fluid I6 and grinding uid I1. The grinding fluid I1 serves to promote grinding and is hereinafter termed grinding fluid, and may be an oil, such as a mineral, animal, or vegetable oil, preferably treated to embody one or more ingredients, such as sulphur or chlorine compounds, to improve the grinding action. Oils of this nature may be loaded, in a known manner, with such sulphur compounds or chlorine compounds or both, for example sulphur chloride. The oil which is preferably used with this apparatus is a grinding oil of the insoluble type meaning that it is not soluble in Water. n

The grinding fluid is insoluble in the cooling fluid and is preferably such that 'it readily separates from the cooling fluid during gravity flow fluid I1 and coolant fluid I5 in the tank II, a pair of vertically extending glass or other transparent panels 43 and 44 are provided in the side fa-ce 31 of the tank I I.

The channel iron 3S preferably is supported on a plurality of angle-iron brackets 52, 52a, 52h, and 52o (Fig. 10). A plurality of screws or bolts not shown serve to detachably secure the channel iron 36 to the brackets 52, 52a, 52h and 52e, so that the channel iron 36 and the mechanisms supported thereon to be hereinafter described may be readily removed from the tank II when desired.

The pan I5 is preferably shaped to t within the upper portion of the tank I Il and is supported upon a plurality of angle-iron brackets 53, 53a,

through the unit at substantially normal room.

temperature. The liquid supplied for cooling the work piece is preferably water.

The tank II is preferably formed as a rectangular sheet metal welded-up structure having triangularly shaped reinforcing brackets or plates I8, I9, and 2| which are welded to opposite sides of the tank and also to the bottom thereof. A plurality of transversely extending brackets 22, 23, 24, 25, 26 and 21 are welded to the front and back faces of the tank. These brackets have two functions, namely to reinforce and strengthen the front and back surfaces of the tank and also serve to position and locate partitions within the tank to be hereinafter described.

A pair of partitions 28 and 29 are welded together in spaced relationship with each other by means of brackets 30, 3|, 32 and 33 (Fig. 11). It should be noted that in Fig. 10 the partition 28 extends from the side face 31 of the tank II to the transverse bracket so that fluid may pass around the upper end of the partition 23 as shown in Fig. 10. Similarly the partition 29 extends from the opposite side face 38 of the tank II to the brackets 32 so that there is an open space between the lower end of the partition 29 and the side face 31 so that fluid may pass therethrough. The partitions 28 and 29 being of a unitary construction are arranged so that they fit between the transverse brackets 24-25- and 26-21 respectively so that the partition unit maybe readily removed for cleaning out the tank II.

Another partition 34 (Figs. l and 10) is supported against the transverse brackets 22 and 23 and isl held in position thereagainst by a plurality of screws 35 which are screw threaded into a transversely extending inverted channel iron 36 bolted to the upper portion of the tank I I. It should be noted in Fig. 10 that the partition 34 extends from the side face 31 of the tank II to a point'spac'ed from the side face 38 of the tank II so that fiuid may flow around the upper end of the partition 34 (Fig. 10) The partitions 23y 29 and 34 serve to divide the tank II into a plurality of chambers 39, 4i), 4I and 42. Due to the fact that the partitions do not extend across the entire width of the tank, fluid may flow in a tortuous path from the chamber 39 around the upper end of the partition 28, through the chamber 40, around the lower end of the partition 29, through the chamber 4I, and around the end of the partition 34 into the chamber 42. This relatively long path of travel of uid entering at the lower end of the chamber 39, as shown in Fig. 10, serves to facilitate gravity separation of the oil or grinding fluid I1 from the water or coolant fluid I6 as shown in Fig. 2. To facilitate visible indication of the level of the grinding It' is desirable to provide a relatively long path 'of flow for the refuse fluid (swarf grinding fluid and cooling uid) returning from the grinding machine so that the swarf may be settled out and the grinding and cooling nuids separated from each other before dropping into the tank I I. This operation may be accomplished by providing a relatively long pan but in order to minimize the amount of floor space required for the unit a relatively compact pan is provided which is arranged so that the fluid ows in a tortuous path so that a relatively long flow thereof may be obtained in a comparatively compact area. This is preferably accomplished by providing the pan I5 with a plurality of transversely extending parti'- tions 45, 46 and 41 (Figs. 1 and 4). These partitions vextend across the entire width of the pan and are welded in place to the sides of the pan. The partitions 45, 46 and 41 divide the Apan I5 into a plurality of transversely extending compartments 48, 49, 50 and 5I which are connected in a manner to be hereinafter described at alternately opposite ends so as to provide a tortuous path of fiow for the fluid. The bottoms of the compartments 43, 49, 59 and 5I are preferably arranged so as to form a continuous sloping surface so that fluid may flow through the compartments by gravity. As shown in Fig. 5, the compartment 48 is provided with a sheet metal bottom plate 55 which slopes toward the right" (Fig. 5) and is welded to one side of the pan I5 and to the partition 45. Fluid passing through the co l-- partment 48 moves in a direction toward the right (Fig. 5) and passes through a port or aperture 55 `inthe partition 45 (Fig. 6) into the compartment 49. The compartment 49 is similarly provided with a sloping bottom plate 51 which slopes toward the left (Fig. 6) and is welded to the partitions 45 and 46. Fluid entering the compartment 49 through the port or aperture 56 flows toward the left (Fig. 6) and through a port o1' aperture 58 in the partition 46 into the compartment 50. The compartment 50 is provided with a bottom plate 59 which slopes toward the right (Fig. 7) and is welded to the partitions 46 and 41. Fluid from the compartment 50 flows through a port or aperture Si) in the partition 41 into the compartment 5I. The compartment 5I is provided with a bottom plate 6 I which slopes toward the left (Fig. 8) and is welded to the partition 41 and the side of the pan I5. The bottom plate 5I has a gradual slope toward the left except as it approaches the left hand end of the compartment 5I (Fig. 8). At this point thebottom plate 6I drops abruptly as indicated by the portion 62 to convey fluid to an aperture 63 from which the :is :desirable to `provide a plurality `of :obstructions such .as dams or l.shallow partitions which serve lto produce an :agitating effect on :the fluidas .it passes through the :pan I5. IThis agitation'of the -fiuid serves-'5to v.facilitate fthe settling-:out ofrswar' :(metal particles, `abrasive rgrit, reto.) and also .serves-,to accelerate the #separation of the grind-V king liquid ifromthe 'coolingliquid `As illustrated in Figs. 53 andra the gcornpartrnentia is provided withrareadilyremovabletray comprising ,a longitudinally extending vertical 'strip .65 .to lwhich `is Awelded ppposedstrips or .dams 6 8 and 69. ,'Ihis tray unitis arranged to llt loosely within the compartment 4v81so that. itmay be readily removed when it is Adesired to cleanout thejpan I5.

Asimilar tray is provided for the compartment 49 comprising a longitudinally extending strip V65a having opposed strips or dams 66a and lila which are welded to opposite sides thereof,l and spaced therefrom strips or dams 68a and 69a. This vrunit like the one previously described ilts loosely1 within the compartment 49 so that itmay be readily nremoved ltherefrom when desired.

A similar'tray is provided for the compartment 50 comprising ,a longitudinallyr extending strip 65h yhaving.opposedstrips ordams 66h and 61h welded thereto and spaced therefrom strips or `dams 68h and 69h. Asimilar tray is providedfor the comn partment 51| comprising fa longitudinally,extendm .ing strip chaving welded.thereto.opposedstiips .or dams Staand 61o, .and spaced .therefrom fopposed Astrips .or Jdams A68o `.and .69s.

It ,should be noted that the Yports or passages ,56,58 and-60 in thepartitions 45, ,4S and 41 are spaced from the bottoms -of the compartmentsso that thelower portion of these partitions serve as additional damsA or obstructions to the flow of fluid through the Ypan I5.

It will -be readily apparent from the foregoing disclosure `that when uid is passed through. a

pipe. 1,5, from thevgrinding.machineit will flowA by gravity in the path of the arrows as indicated inFig. 4. ,.Eachof thestrips Aor dams vabove defscribedserve to lretard the flow of fluid `through the vcompartments v58, 49, 5i) and 5I so as to accelerate the settling-out and collecting of swarf from the lluid in the pan and also serve to agitate the fluid to facilitate a separation of the grinding fluid from the cooling fluid before the fluids pass through the aperture 63 (Fig. 8) into the tank I I.

A plurality of holes lll, 'II and l2 are provided in `the `partitions 45, it and 41 respectively. These holes are slightly above the bottom of' each respective compartment and serve to facilitate flushing out the Apan when it is desired to .clean the same.

It is desirable from time to time Vduring use of this plural fluid unit to clean Vout the accumulation of swarf in the pan i5. This is preferably accomplished by removing trays from each of the compartments 48, t9, 5S and 5I, then scoop- `ing outsthe vbulk of the swarf accumulated therein,

after which the tray ,may be readily flushed out with a hose to clean the same if desired.

'The V*tank II `is provided with an overflow pipe 'I4 to prevent excessive filling of .the `tank I I with fluid.

It is desirable to provide a circulating means to the grinding fluid pump 8i.

for the-grinding fluid and the coolingf'luid sothat `they maybe separately pumped fromtheytank -II to one :ormore grinding machines. As .illustrated .in Fig.,2, .a motor driven pump unit comprising an electricmotor lli and a pump i1 is supported on the channel iron 36. The pump 11 is located in the coolant fluid chamber 4Z of the tank II, .and is vpositioned in the lower part of the compartment where it will draw coolant fluid therefrom. Coolant iluid I8 from the compartment is passed through a pipe 'IB .and is conveyed in a 4manner to be hereinafter described to the work piece being ground.

The channel iron se also supports va motor driven pump unit comprising an electric `motor BI] .and a pump Sl which draws grinding fluid I7 Yfrom the upper portion of the .tank II. ltjis desirable to provide a illtervfor the grinding fluid to-.remove any stray particles of grit either metallic or abrasive therefrom before the fluid is con- 'veyed to the grinding machine. As illustrated in Figs. 2 and 12, grinding fluid I'l from Ythe upper Vportion of the ktank II passes through a pipe vIl2,

through a valve 83, through a check valve 84 and through a fluid filter 85, through the pipe 86 The pump 8| serves to force grinding fluid at a relatively high pressure and a relatively low volume through the pipe 8'! in a manner to be hereinafter described. An adjustable pressureirelief valve d8 is provided vin the pipe line 8l whereby excess 'fluid under Ypressure may be'returned to the tank side of the pump so as to facilitate maintaining a predetermined pressure of the grinding fluid.

Grinding fluid passing through the pipe 8l may he conveyed to one or more grinding machines.

'The pipe 'l is connected by a valve 9! With a manifold 92 having a plurality of independent control valves et, da and Q5 for controlling the `passage of grinding fluid at a relatively high pressure and a relatively low volume through a plurality of spaced nozzles or jets 95 (only one of which has been illustrated in the drawings).

This nozzle or jet construction may be substantially identical with that shown in the above mentioned prior pate-nt and pending application.

`The jets or nozzles et are preferably arranged so that fluid at a relatively high pressure and a 4 relatively low volume is passed onto the grinding `wheel 91 at a point adjacent to the place of contact between the grinding wheel 91 and the work `piece 98 being ground to facilitate the grinding operation. If desired the system may be provided with a pressure gage 99 which is connected by means of -a valve Ide with the pipe el' so that the grinding `fluid pressure may be readily l`checked when desired.

If it is desired to connect the plural fluid unit to more thanone machine, fluid passing through the pipe 8l may similarly' pass through a valve 9Ia to a manifold G20; and through a plurality of manually operable control valves`93a, 94a and 95a to a plurality of jets 56a so as to convey grinding fluid at the desired pressure and quantity to the grinding wheel 91a at the place of wheel 91h at the place of contact between the grinding wheel 81h and the work piece 98D. If desired each of these additional grinding machines may be provided with separate pressure indicators or gages 99a and 90b which are connected by valves |a and |00b with the pipe 81 so that the grinding fluid pressure supplied to each machine may be readily checked When desired.

Cooling fluid from the pump 'I1 passing through the pipe 90 at a. relatively low pressure and a relatively large volume is conveyed through a valve |0| to a coolant nozzle |02 which is arranged to convey a relatively large volume of' 'coolant fluid to the surface of the Work piece 92 being ground. Similarly coolant fluid passing through the pipe 90 may pass through a valve |0|a to a coolant nozzle |02a to supply a relatively large volume of coolant fluid to the surface of the work piece 98a being ground. Coolant fluid in the pipe 90 may be also conveyed to a third grinding machine through a valve |0Ib to a coolant nozzle I 02h to supply coolant fluid in a relatively large volume to the surface of the work piece 98h being ground.

By providing a plural fluid unit I0 of a suitable size and capacity, either one or a plurality of grinding machines may be supplied with the required amount of grinding fluid and cooling fluid to perform the desired grinding operation.

Grinding fluid and cooling fluid together with swarf from the grinding operation drain into reservoirs |03, |0311 and |03b on each of the grinding machines. Fluid may be pumped from the reservoirs |05, |03a and |031) through a plurality of pipes |55, |04a and |041) by means of a fluid pump |05 which is driven by an electric motor |I0. The pump |05 passes refuse fluid through a pipe |06, through a valve |01, through a check valve |08 which connects with the pipe T5 to convey the refuse fluid and swarf to the pan I5. As previously described, as fluid is passed through the tortuous path formed within the pan i5 swarf is settled-out therefrom and the grinding fluid is separated from the collant fluid due to the differing specific gravities thereof. The grinding fluid and cooling fluid then passes from the pan I5 through the aperture 53 into the chamber 39 in the tank (Fig. 10) and flows through a tortuous path as indicated by the arrows in Fig. 10 into the chamber 42 where the fluid is separated as indicated in Fig. 2 and ready to be circulated to the one or more grinding machines as previously described.

The electric motors 16, 80 and |I0 for driving the pumps 11, 8| and |05 respectively receive power from a suitable source such as indicated by the power lines II I (Fig. 13) A main switch I I2 serves to close the circuit and to simultaneously start the three pump motors 16, 80 and l I0.

A sheet metal hood |I5 surrounds the motors i6 and 86 and the pump BI This hood is preferably readily reniovable from the tank by means of a pair of handles |I6 and II1. In order to facilitate cleaning out the tank II when desired, the pan I5 is preferably made so that it may be readily removed therefrom by means of a pair of opposed handles H8 and IIS to facilitate access to the tank II. If it is desired to clean out the .tank I I, the pan I5 is rst removed after which the partition assembly 28-29 may be readily removed and the partition 34 removed by ilrst removing the screws 35 after which any accumulation of swarf or sludge may be removed from the bottom of the tank II. In case it is desired to flush out the tank II after cleaning, the bottom of the tank is provided with a central port |20 (Fig. 10) which is connected by a pipe I2I with a pipe elbow |22 having a drain plug |23 (Figs. 2 and 10). By removing the plug |23, the tank II may be readily flushed and drained through the pipe |2| and the elbow |22.

The operation of this improved plural fluid grinding apparatus will be readily appreciated from the foregoing disclosure. The desired amount of coolant fluid such as water may be put into the tank I I in any suitable manner or may be poured into the compartment 48 and caused to pass through the tortuous path above described and through the aperture 63 into the tank II. Similarly the desired amount of grinding fluid, such as suitable oil or oil compounds, may be conveyed to the tank I I directly or in a manner above described namely through the pan I5 into the tank I I. The main switch I I2 may then be closed to start the pump driving motors 16, and I|0 which serve in a manner above described to pump grinding fluid at a relatively high pressure and a relatively low volume to one or more grinding machines as desired. The coolant pump 11 serves to convey coolant fluid at a relatively low pressure and a relatively large volume to one or more machines as desired to facilitate the grinding operation. Similarly the fluid pump |05 which is started simultaneously with the other pumps serves to return the refuse fluid from the grinding machine reservoirs |03, |03a and I03b to the plural fluid unit I0 where the swarf is settled-out and the grinding fluid separated from the coolant fluid in its passage through the pan l5 in a manner above described and then passes into the tank I I where the two fluids separate due to their different specic gravities so that the coolant fluid accumulates at the bottom of the tank vand the grinding fluid floats on top thereof. This vcleaned grinding fluid and cooling fluid is then ready for being reconveyed to the grinding machine for further grinding operations.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and notl in a limiting sense.

I claim:

l. A plural liquid unit for grinding machines havingy a tank having an open top arranged to contain a grinding liquid and a cooling liquid each of which has a different specific gravity so that the cooling liquid settles in the bottom of the tank While the grinding liquid separates into a layer in the upper portion of the tank, a pump chamber in said tank, independent motor driven pumps for separately pumping grinding liquid from the upper portion of said chamber and cooling liquid from the lower portion of said chamber, a pan removably mounted on top of said tank to receive refuse liquid from a grinding machine consisting of a mixture of grinding liquid-coolant liquid andv swarf, said pan being shaped to mate with the open top of said tank, a plurality of transverse partitions in said pan arranged to form a relatively long path for the gravity flow of refuse liquid therethrough to facilitate settling-out and collecting swarf in saidfpan and to facilitateseparation of the grinding and cooling liquids before flowing into said tank, and having a discharge aperture in said pan at the end. of the long path to convey liquid into said tank.

2. In a plural liquid unit, as claimed in claim l, in combination with the parts and features therein specied in which the partitions are provided with passages through alternate ends, said passages being arranged to form a relatively long tortuous gravity flow of liquid through the pan, and a plurality of transverse baffles between said partitions to agitate said liquid so as to facilitate settling-out swarf and to facilitate. separation .of the grinding and cooling liquids before ilowing into said tank.

3. In a plural liquid unitr as, claimed in claim l, in combination with the parts and features therein specified in which the partitions areprovided with passages through alternate ends, said passages being arranged to form a relatively long tortuous gravity ilow of liquid through the pan, a bottom for said pan betwen said partitions which slopes gradually from the liquid entry to the discharge to facilitate gravity flow of liquid therethrough, a readily removable baille assembly between each of said adjacent partitions including a longitudinally extending baille plate having a plurality of spaced transversely extending pailies to agitate the refuse liquid from one or more grinding machines to facilitate settling-out swarf and to facilitate separation of the grinding and cooling liquids, and having a passage in the bottom of said pan located at the end of the tortuous liquid path for conveying the separated liquids into said tank.

4. ln a plural liquid unit, as claimed in claim l, in combination with the parts and features therein specified in which the partitions are provided with passages through alternate ends, i

said passages being spaced from the bottom of said pan and arranged to serve as baffles for refuse liquid flowing therethrough, and a readily removable baffle assembly in each of the compartments between the partitions including a longitudinally extending baille plate having a plurality of spaced transversely extending bailles, said assemblies serving to facilitate settling and collecting swarf in said pan and being removable to facilitate cleaning swarf from said pan when desired.

5. In a plural liquid unit, as claimed in claim 1, in combination with the parts and features therein specified' of a plurality of removably spaced partitions to form a plurality of spaced compartments in said tank, each of said partitions being shorter than the Width of the tank, and being arranged to form opening at opposite ends thereof to form a tortuous path for liquid in said tank to facilitate completion of the separation of the grinding liquid from the cooling liquid.

6. A plural liquid unit for grinding machines having a tank having an open top arranged to contain a grinding liquid and a cooling liquid each of which has a different specific gravity so that the cooling liquid settles in the bottom of the tank while the grinding liquid separates into a layer in the upper portion of the tank, a pump chamber in said tank, a pair of motor driven liquid pumps for separately pumping grinding liquid from the upper portion of said chamber at a relatively high pressure to the surface of the grinding wheel for promoting grinding and small volume and for pumping coolant liquid from the lower portion of said chamber at a relatively low pressure and large volume to the workpiecebeing ground to cool the workpiece, apan mount ed on said tank to receivel refusev liquid from a grinding machine consisting of a mixture of grinding liquid-coolant liquid and swarf, said pan being shaped to mate with the open top' of said tank, a plurality of spacedy lugs within said tank to support said pan, and a plurality of transverse partitions arranged to form a relatively long tortuous path for the gravity ilow of refuse liquid therethrough to facilitate settling-out and collecting swarf in said pan and to facilitate separation of the grinding and cooling liquids before they flow into said tank.

7. A plural liquid unit for grinding machines having a pan to receive'refuse liquid from one or more grinding machines including ai grinding liquid-cooling liquid and swarf, a plurality of transverse partitions in said pan forming a plurality of adjacent transversely extending compartments, said partitions beingproyided with a passage through alternateends to form a tortuous path for liquid flowing in one direction through said pan, the bottom of said compartments sloping progressively to facilitate continuous flow of,

liquid therethrough by gravity, a plurality of bailies extending transversely across said compartments, said baffles and passages serving to retard the ilow of liquid so as to cause an agitating action of the liquid as it ows through said compartments to facilitate settling-out and collecting swarf in said pan and to facilitate separation of the grinding and cooling liquids, a relatively large tank having an aperture on the top shaped to mate with and support below said pan, said pan having an opening in the bottom of said pan whereby the separated liquids flow into said tank, and a plurality of removably spaced partitions in said tank, each of said partitions being shorter than the width of the tank and arranged to form a tortuous path for liquid flow in the opposite direction within said tank, and a pump compartment adjacent to one end of said tank whereby the separated grinding liquid and cooling liquid may be separately pumped to one or more grinding machines.

8. A plural liquid unit for grinding machines having a tank which is open at the top and arranged to contain a grinding liquid and a cooling liquid each of which has a different specic gravity so that the cooling liquid settles in the bottom of the tank while the grinding liquid separates into a layer in the upper portion of the tank, a pump chamber at one end of said tank, independent motor driven liquid pumps in said unit for separately pumping .grinding liquid from the upper portion of the chamber at a relatively high pressure and low volume to the surface of the grinding wheel for promoting grinding and for pumping coolant liquid from the lower portion of said chamber at a relatively low pressure and large volume to the workpiece being ground to cool the workpiece, a pan mounted on top of said tank which is shaped to mate with the open top of said tank and to receive refuse liquid consisting of a mixture of grinding liquid-cooling liquid and swarf from plurality of grinding machines, a plurality of transverse partitions in said pan arranged to form a relatively long tortuous path for gravity flow of refuse liquid therethrough in one direction, a plurality of transverse bailles between said partitions to agitate said liquid as it ilows therethrough to facilitate settling-out and collecting swarf in said pan and to facilitate separation of the grinding and cooling liquids, the bottom of said pan being provided with an aperture at the end of the tortuous path to allow the separated grinding and cooling liquids to ow into said tank, and a plurality of partitions in said tank which are arranged so that the liquids ow in a tortuous path in the opposite direction into said pump chamber for recirculation to said grinding machines.

9. A central unitary plural liquid unit for separately supplying a grinding liquid and a cooling liquid to a plurality of grinding machines having an open top tank arranged to contain a grinding liquid and a cooling liquid each of which has a different specic gravity, a plurality of spaced partitions in said tank arranged to form a tortuous path for liquid flow in one direction, a pump compartment adjacent one end of said tank, independent liquid pumps for separately pumping grinding liquid and cooling liquid to a plurality of grinding machines, a pan which is shaped to mate with the open top of said tank for receiving refuse liquid consisting of a mixture of grinding liquid-cooling liquid and swarf from said grinding machines, and means including a plurality of partitions and baies in said pan to 12 produce a gravity flow of liquid therethrough in the opposite direction in a tortuous path to facilitate settling-out and collecting swarf in said pan and to facilitate separation of the grinding and cooling liquids before passing into said tank.

CHARLES C. ALVORD.

REFERENCES CITED The following references are of record in the iile of this patent:

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